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TRC-70
CIRCUIT DESCRIPTION
«
Backup
The TRC-70 backs up data in two ways. The first is
a semipermanent backup that backs up memory chan-
nel data in the nonvolatile memory
EEPROM.
The
second is a lithium cell that backs up the operation
status in the CPU RAM.
The CPU backup is performed by monitoring the CB
(13.6 V) line. If the voltage falls below the prescribed
level, the CPU STOP pin is activated and CPU power
consumption is reduced.
When the power consump-
tion is low, the CPU
stops generating clock signal,
which places each port is at a high impedance level.
WwW
a u
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sToP
CPU
4
5V
pt
84) vce
BA300
¢
System reset circuit
IC305 (M51951BML)
is the system
reset !C that
monitors the power supply voltage.
If the voltage falls
below the prescribed level, it outputs a reset signal to
®
the main CPU to stop execution and inhibit memory
LA- -----4t----t%-
write functions.
°
If the power supply voltage again exceeds the pre-
®
|!
scribed level when the power is on, the reset signal is
/
released, the main CPU is initialized, and execution is
resumed after the time constant of R375 and C379
has elapsed.
©
RES
RESET |
RESET
RESET
—e—
5V
1€305 (MSISSIBML)
IC306
IC307
_—_—
{se
2
1c302
CPU RESET
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To IC3tl WR pin through [C308
Fig. 9 Reset circuit and timing chart
12
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